Figure 1.

Conceptual framework, task and psychophysical performance. a, Schematic showing all possible statistical dependencies between choices and spike counts on the preceding and current trial. b, After the monkey acquired fixation on a central fixation point the stimulus was presented for a fixed duration of 2 s, followed by two choice targets above and below the fixation point. After a saccade to the correct choice target, the monkey was rewarded with a liquid reward. c, The average psychophysical performance of both monkeys across all sessions (n = 75) is shown (black). For each session, a positive and negative choice was defined as a choice toward the neuron's preferred or null disparity (near or far), respectively. Note the horizontal shift of the psychophysical curves with respect to each other when they were computed separately for trials preceded by a positive choice (yellow) or negative choice (blue), indicating a systematic bias introduced by the choice on the preceding trial. Data points are binned averages across sessions. Error bars are SEs. Solid lines represent the mean fits (cumulative Gaussians) across sessions.